Almost all states say once product leaves the door without being purchased, it's considered stolen, even if it was recovered. Wal-Mart either has state of the art cameras that can read text messages off of phones, or shitty 140p cameras that can't even identify a make of a car. I've worked with both. If they stopped him, chances are they followed him from a distance, got the plate, and gave it to the cops, who after a few hours/days of looking over footage will knock on your door asking for him.

If you bring him in, which ofc I recommend, they'll probably prosecute because he ran, it's up to the manager. We always did, and we always permanently trespassed. The reason why I recommend it is because turning yourself in shows integrity, something LPs and courts respect even if they do prosecute, and will help out a lot, even after it's dropped off the record. Hell, you might get lucky and they'll forgive you by not calling the cops, don't count on it though.

You could also just ignore it, chances are they'll forget him after a few years if they missed the plate, but the risk of them identifying him anyways isn't something I'd take, especially since running makes everything ten times worse. It's up to you, you can gamble to get off scot free, or man up and take a reduced punishment.